The present invention relates generally to liquid dispensers, and particularly to a dosing pump for a viscous liquid dispenser and a dispenser incorporating such a pump.
Viscous liquid dispensers are well known in the art for dispensing any manner of viscous liquid, for example lotions, soap, and the like. The conventional dispensers utilize a wide variety of pumping mechanisms which allow a user to depress or manipulate a pump actuator in order to dispense liquid from the dispenser. Exemplary devices are shown, for example, in U.S. Pat. Nos. 5,810,203; 5,379,919; 5,184,760; and 4,174,056.
Conventional dispensers and pump mechanisms are configured generally for vertical mode operation. In other words, the dispenser stands generally upright with the pumping device configured at the top of the unit. These pump devices are generally vented around the stem of the pump and should a user attempt to use the dispenser in a horizontal mode, the dispenser will, in all likelihood, leak around the pump stem.
An additional problem noted with conventional pumps, particularly lotion or soap dispenser pumps, is that there is a tendency for leakage of residual liquid left in the pump head. Certain types of combination pumps, such as peristaltic pumps common to liquid skin care product dispensers, incorporate a spring and ball check valve system in the discharge area to prevent leaking. However, this type of check valve system is relatively expensive and complicated, and the components may be subject to corrosion and/or sticking when used with certain chemical compositions.
Diaphragm type valves are used in certain applications, for example squeeze actuated bottles of hand lotion, in which the bottle is squeezed by a user to provide the liquid pressure required to open the diaphragm valve. However, with these configurations, there is no discreet control over the amount of liquid dispensed.
Thus, there is a need in the art for a dosing pump that can dispense a metered amount of viscous liquid in a horizontal mode while preventing leakage from around the pump mechanism without complicated check valve devices.
Objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The present invention provides a unique dosing pump that is particularly well suited for viscous liquid dispensers, for example, soap dispensers, lotion dispensers, and the like. The pump may be oriented in a generally horizontal configuration and thus allows greater flexibility as to the design and configuration of a dispenser utilizing the pump.
The pump may be utilized with any manner or shape of dispenser. The dispenser will generally comprise a housing member or members that define a liquid reservoir. The pump includes a pump chamber that is in communication with the liquid reservoir. In one embodiment, the pump chamber may be defined internally of the dispenser housing. For example, the pump chamber may comprise and integrally molded component of the housing. In an alternative embodiment, the pump chamber may be configured on the outside of the reservoir or housing with a channel or passage defining a liquid communication path between the reservoir and the pump chamber. It should be appreciated that any number of configurations may be utilized to define a pump chamber that is in fluid communication with a liquid reservoir.
The pump chamber has a volume that generally defines the metered dose of liquid to be dispensed. A dispensing orifice is defined in the pump chamber. The orifice may be defined in any wall member of the chamber, or in one particular embodiment according to the invention, the orifice is defined in a bottommost wall of the pump chamber.
A pump mechanism is configured with the pump chamber to pressurize liquid within the pump chamber upon actuation of the pump mechanism. The pump mechanism may be any member or configuration of components that pressurizes the liquid contained within the chamber in order to expel or dispense the liquid through the dispensing orifice. In one particular embodiment according to the invention, the pump mechanism includes a pump cylinder that is slidably disposed and retained in the pump chamber. The pump cylinder is moveable from a rest position to a pressurizing position. The cylinder may be biased to the rest position with a spring or other biasing element.
An actuator is configured with the pump cylinder and provides a device for a user to move the pump cylinder to its pressurizing position in order to dispense liquid out the dispensing orifice. The invention is not limited to any particular type of device for actuating the pump. In one particular embodiment, the actuator may comprise a panel member that is pivotally mounted to the dispenser housing. The panel member rests against a front end of a pump cylinder and thus moves the pump cylinder or shaft upon a user depressing the panel member. In an alternate embodiment, the actuator may comprise a plate, button or the like attached directly to the front end of the pump cylinder. The actuator may be configured in any shape to contribute to the aesthetically pleasing look of the dispenser.
A check valve mechanism is operably disposed in the opening between the pump chamber and the liquid reservoir. Upon actuation of the pump, the check valve mechanism moves to seal the pump chamber so that the liquid within the chamber can be pressurized. Upon release of the pump actuator, the check valve mechanism moves to unseal the pump chamber so that a metered amount of viscous liquid is able to flow automatically from the reservoir into the pump chamber for dispensing upon the next subsequent actuation of the pump. The check valve mechanism may take on a number of configurations, such as a ball check valve, a flap member, and the like. In one particular embodiment, the check valve mechanism may comprise an elongated shuttle type valve that is slidable within the opening between the pump chamber and reservoir. The shuttle valve includes a sealing member, such as an elastomeric cap, that seals the opening upon actuation of the pump device. Upon release of the pump, the shuttle valve unseals, and liquid is free to flow past the shuttle valve and into the pump chamber. In the embodiment wherein the shuttle valve includes an elastomeric cap or similar type of sealing member, movement of the pump cylinder back to its rest position causes a slight vacuum to be drawn in the pump chamber before the elastomeric cap unseats. This vacuum is beneficial in that any liquid remaining in the dispensing orifice will be drawn back into the pump chamber.
A sealing member is disposed within the pump chamber to seal the dispensing orifice upon an initial movement of the pump cylinder towards the pressurizing position. For example, in one embodiment the sealing member may remain stationary relative to the pump cylinder and the pump chamber as the pump cylinder is moved initially towards its pressurizing position. In an alternate embodiment, the sealing member may have a longitudinal length so as to move with the initial movement of the pump cylinder while maintaining a seal of the dispensing orifice. As long as the dispensing orifice is sealed by the sealing member and the pump cylinder is moved towards the pressurizing position, liquid within the pump chamber is pressurized.
Upon further movement of the pump cylinder towards the pressurizing position, the sealing member eventually moves and unseals the dispensing orifice. At this point, liquid within the pump chamber will flow out of the dispensing orifice.
Upon initial return movement of the pump cylinder to its rest position, the sealing member remains unsealed relative to said dispensing orifice. So long as the check valve does not immediately unseat, at least a partial vacuum is drawn in the pump chamber causing any liquid in the dispensing orifice to be drawn back into the pump chamber. Upon further movement of the pump cylinder towards its rest position, the sealing member moves to seal the dispensing orifice and, after the check valve has unseated, liquid is drawn from the reservoir past the check valve and into the pump chamber.
This sealing member may be, for example, a multiple lip elastomeric seal disposed circumferentially around the pump cylinder and sealingly engaged against the interior wall of the pump chamber. The sealing member may be moved to seal and unseal the dispensing orifice by engagement members defined on the pump cylinder. For example, a first engagement member may come into contact with and move the sealing member off of the dispensing orifice as the pump cylinder is moved towards the pressurizing position. A second engagement member may come into contact with and move the sealing member over the dispensing orifice as the pump cylinder is subsequently returned to its rest position.
The pump cylinder may include an internal longitudinally extending channel defined therein having an inlet and an outlet. Once the dispensing orifice is unsealed, pressurized liquid within the pump chamber may enter the channel inlet and be dispensed out the channel outlet, the outlet being aligned with the dispensing orifice. In this configuration, the longitudinal channel thus defines a by-pass path for the liquid around the sealing member.
The present invention also includes any manner of dispenser incorporating the unique dosing pump as described herein.
The invention will be described in greater detail below through embodiments illustrated in the figures.